Detection and characterization of CD133+ cancer stem cells in human solid tumours.
BACKGROUND
Osteosarcoma is the most common primary tumour of bone. Solid tumours are made of heterogeneous cell populations, which display different goals and roles in tumour economy. A rather small cell subset can hold or acquire stem potentials, gaining aggressiveness and increasing expectancy of recurrence. The CD133 antigen is a pentaspan membrane glycoprotein, which has been proposed as a cancer stem cell marker, since it has been previously demonstrated to be capable of identifying a cancer initiating subpopulation in brain, colon, melanoma and other solid tumours. Therefore, our aim was to observe the possible presence of cells expressing the CD133 antigen within solid tumour cell lines of osteosarcoma and, then, understand their biological characteristics and performances.


RESULTS
In this study, using SAOS2, MG63 and U2OS, three human sarcoma cell lines isolated from young Caucasian subjects, we were able to identify and characterize, among them, CD133+ cells showing the following features: high proliferation rate, cell cycle detection in a G2\M phase, positivity for Ki-67, and expression of ABCG2 transporters. In addition, at the FACS, we were able to observe the CD133+ cell fraction showing side population profile and forming sphere-clusters in serum-free medium with a high clonogenic efficiency.


CONCLUSIONS
Taken together, our findings lead to the thought that we can assume that we have identified, for the first time, CD133+ cells within osteosarcoma cell lines, showing many features of cancer stem cells. This can be of rather interest in order to design new therapies against the bone cancer.
Tirino
Virginia
V
Dipartimento di Medicina Sperimentale, Sezione di Istologia ed Embriologia, Seconda Università degli Studi di Napoli, Napoli, Italy.
Desiderio
Vincenzo
V
d'Aquino
Riccardo
R
De Francesco
Francesco
F
Pirozzi
Giuseppe
G
Graziano
Antonio
A
Galderisi
Umberto
U
Cavaliere
Carlo
C
De Rosa
Alfredo
A
Papaccio
Gianpaolo
G
Giordano
Antonio
A
D000071916:AC133 Antigen; D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters / Q000032:analysis; D015703:Antigens, CD; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D002469:Cell Separation; D005434:Flow Cytometry; D016195:G2 Phase; D006023:Glycoproteins; D006801:Humans; D019394:Ki-67 Antigen / Q000032:analysis; D009363:Neoplasm Proteins / Q000032:analysis; D014411:Neoplastic Stem Cells / Q000473:pathology*; D012516:Osteosarcoma / Q000473:pathology*; D010455:Peptides
C116614:ABCG2 protein, human; D000071916:AC133 Antigen; D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters; D015703:Antigens, CD; D006023:Glycoproteins; D019394:Ki-67 Antigen; D009363:Neoplasm Proteins; C000606023:PROM1 protein, human; D010455:Peptides